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PubMed1976

Congenitally corrected transposition of the great vessels: localization of the site of complete atrioventricular block using his bundle electrograms.

Complete atrioventricular block proximal to the bundle of His in a patient with congenitally corrected transposition of the great vessels was documented using His bundle electrograms. The spontaneous rhythnm probably originated from the bundle of His and was responsive to carotid sinus massage, atropine and isometric and treadmill exercise. These electrophysiologic observations are consistent with recent anatomic studies of congenitally corrected transposition of the great vessels.

Adult↗

PubMed1978

[Variants of development of complete atrioventricular block. Prognosis in disorders of intraventricular conduction].

In a group of patients with complete atrioventricular block admitted for implantation of a cardiac stimulant, 15 out of 74 patients (20.3%) had normal intraventricular conduction before the block, while 59 (79.7%) had disorders of intraventricular conduction. A combination of right bundle-branch block with block of the anterior limb of the left branch was the most frequent occurrence (37.8%). Comparison of the QRS complexes in maintained atrioventricular conduction with those in complete antrioventricular block showed that among patients with disorders of intraventricular conduction complete atrioventricular block was of a proximal character in 45.5% and of a distal character in 54.5% of cases. There was a high risk of development of complete atrioventricular block in patients with right bundle-branch block combined with block of the anterior limb of the left branch; it was found to be 41.2% at an average follow-up period of 23 months.

Adolescent↗

PubMedDate not supplied

Comparison of prizidilol, a new antihypertensive drug with combined arteriolar vasodilator and beta-adrenoceptor blocking actions, with hydralazine and propranolol in conscious dogs with chronic atrioventricular block.

The effects of prizidilol, a novel antihypertensive agent with vasodilator and beta-adrenoceptor blocking actions, were compared with those of hydralazine and propranolol in conscious dogs with chronic atrioventricular block. Prizidilol significantly increased atrial rate, mainly through reflex reduction of atrial vagal tone in response to its hypotensive effect. Hydralazine also significantly raised atrial rate, while propranolol did not affect it. Prior administration of pindolol, which raised atrial rate to a degree comparable to that achieved with prizidilol and hydralazine, entirely suppressed the atrial tachycardiac effects of both drugs. Prizidilol did not affect ventricular rate on average, whereas hydralazine raised it and propranolol lowered it, both significantly. In some dogs, prizidilol raised ventricular rate like hydralazine; in others, it lowered it like propranolol. In both cases, variation was related to basal ventricular rate. The pattern of these effects was the same as that observed with pindolol. Prior treatment with pindolol almost suppressed the ventricular chronotropic effects of prizidilol, apparently through beta-adrenoceptor blockade.

Adrenergic beta-Antagonists↗

PubMed1982

Anaesthesia in first degree atrioventricular block.

A patient with an intracardiac conduction defect characterised by first degree atrioventricular block due to slowed transmission through the atrioventricular node with increased refractoriness of the node, is described. Asymptomatic first degree block, rarely progressing to transient Wenckebach (type 1 second degree) block had been present for a period of 32 years until general anaesthesia was required, when profound bradycardia attributable to complete atrioventricular block developed abruptly. Subsequent investigations located delayed intracardiac conduction through the atrioventricular node, and indicated excess vagal activity rather than structural disease as the cause. The significance of first degree heart block is discussed in relation to other forms of atrioventricular conduction defect and the current recommendations for temporary pacing for elective general anaesthesia.

Anesthesia, General↗

PubMed1989

[Congenital atrioventricular block and maternal lupus erythematosus. Histologic discovery of tumor of the atrioventricular node].

A case of congenital atrioventricular block in a newborn whose mother presented with systemic lupus erythematosus (SLE) is reported. Despite intensive care the child died a few hours after birth. Serial sections of the heart could be examined. Histology provided information on the appearance and distribution of the lesions. In particular, the sinus node was small for the child's age, and its supplying artery was found to have a hyperplastic media with adventitial sclerosis; the interatrial and interventricular septa showed subendocardial fibrosis invading the adjacent myocardium. Owing to the scarcity of systematic histopathological examinations, such lesions have seldom been described. In addition, a tumour of the atrioventricular node, known as mesothelioma or hemolymphangioma, was discovered. This case is exceptional in that histopathological findings similar to those described in SLE, though rarely as numerous, were associated with a very rare tumour never hitherto described in such a young patient. The relationship between the two categories of lesions is discussed.

Adult↗

PubMed1980

Unsuspected coronary artery disease as cause of chronic atrioventricular block in middle age.

Attention has recently been drawn to the relatively poor prognosis of middle aged patients paced for chronic atrioventricular block when age-linked expectation of life is taken into account, and it has been suggested that this may be the result of underlying coronary artery disease, despite the absence of symptoms to suggest this. It was the purpose of this study to determine the incidence of unsuspected coronary artery disease in middle aged patients presenting with chronic atrioventricular block. Studies were made on a consecutive series of 30 patients aged 45 to 65 (mean age 56 years) with chronic atrioventricular disease who had been referred for pacing. Patients presenting with acute myocardial infarction or angina or with sinuatrial disease without atrioventricular disease were excluded. Coronary arteriography disclosed the presence of severe coronary artery disease in 13 patients. Of the remaining 17 patients, four had congestive cardiomyopathy, two had hypertrophic cardiomyopathy, one had aortic stenosis, and in 10 patients the aetiology of the heart block was unknown. Myocardial revascularisation was undertaken in six patients with paroxysmal atrioventricular block caused by coronary artery disease. Operation did not result in any sustained improvement in atrioventricular conduction.

Aged↗

PubMedDate not supplied

Complete atrioventricular block following myocarditis in children.

Complete atrioventricular block (CAVB) can be either congenital or acquired in children. Acquired CAVB is occasionally seen in myocarditis patients. To determine the etiology, natural history, and outcome of children with acquired nonsurgical CAVB, we retrospectively reviewed nine children who had suffered CAVB caused by suspected infectious myocarditis. All of them had CAVB with a wide QRS escape ventricular rhythm on admission. Three of them had ventricular tachycardia in addition to CAVB. Seven of them had a preceding upper respiratory tract infection. All of them had congestive heart failure. Five of them had Stokes-Adams seizures. Three etiologies were identified in four of the children. All patients received inotropic agents and emergency temporary pacing. In all except one case, the cardiac rhythm returned to sinus rhythm within 10 days. During a follow-up period of 9 to 96 months, all were asymptomatic and drug-free. Electrocardiograms showed that four patients were completely normal, there was complete RBBB in four and left anterior fascicular block in one patient. We conclude that although CAVB associated with myocarditis can be life-threatening, the long-term prognosis is good if patients are diagnosed early and proper management is employed.

Adolescent↗

PubMed1997

Incidence of cardiac sarcoidosis in Japanese patients with high-degree atrioventricular block.

In Japan the majority of sarcoidosis-related deaths are due to cardiac sarcoidosis. One of the most common electrocardiographic abnormalities in patients with this disease is atrioventricular block. This study surveyed the incidence of cardiac sarcoidosis in Japanese patients (40 men and 49 women; mean age, 69.1 years) with high-degree atrioventricular block who were admitted to the hospital to receive a permanent pacemaker. We excluded cases in which sarcoidosis had been diagnosed from the involvement of other organs. Patients with the characteristic signs of sarcoidosis underwent echocardiography, radionuclide imaging, and biopsy. Ten cases (11.2%) of cardiac sarcoidosis were diagnosed, most frequently in women aged 40 to 69 years (8 of 25, 32%). Thus the possibility of cardiac sarcoidosis should be carefully considered in middle-aged or elderly Japanese women who show high-degree atrioventricular block.

Aged↗

PubMed1993

Functional dissociation of cellular activation as a mechanism of Mobitz type II atrioventricular block.

BACKGROUND: Several mechanisms have been advanced to explain Mobitz type II atrioventricular block in the ischemically damaged His-Purkinje system. Only recently, however, has an animal model been developed to study this form of conduction defect in vivo and in vitro. METHODS AND RESULTS: Conduction defects were induced in anesthetized dogs by ischemic damage to the proximal His-Purkinje system after anterior septal artery ligation. Stable 2:1 atrioventricular block, localized within the His bundle or in the proximal bundle branches, was obtained in each dog by atrial pacing at an average rate of 239 +/- 20 beats per minute (n = 12). In vitro studies were then performed from the same hearts. Action potentials and electrograms were simultaneously recorded from the His bundle and the proximal right bundle branch at the site of damage. At slow rates of pacing (40-60 beats per minute), the action potential amplitude was 85 +/- 4 mV, and some cells (10 +/- 3%) showed dissociation from the electrical activity in the bundle. At fast rates (149 +/- 11 beats per minute), during 1:1 conduction, the frequency of cellular dissociation increased to 57 +/- 6% (p < 0.001), and the action potential amplitude decreased (-31 +/- 4%, p < 0.001). The frequency of dissociation closely correlated with the reduction in action potential amplitude (r = 0.87, p < 0.001). These changes were markedly attenuated once 2:1 block developed. The site of block was not constant but rather showed a dynamic behavior with spatial shifting in response to changes in pacing rate or the introduction of extrastimuli. CONCLUSIONS: These results indicate that in the ischemically damaged proximal His-Purkinje system, an increase in rate leads to reduced and asynchronous cellular activation before 2:1 block. The latter provides a more stable activation pattern, because the frequency of dissociation is markedly reduced.

Action Potentials↗

PubMed2004

[Paroxysmal atrioventricular block due to anticholinesterase therapy].

The authors report a case of paroxysmal syncopal complete atrioventricular block due to anticholinesterase therapy occurring after the first administration. The block was reversible. It is therefore important to exclude this cause of atrioventricular block in the elderly in view of the increasing indications of this therapy.

Aged↗

PubMed1986

Significance of advanced atrioventricular block in acute inferior myocardial infarction--a study based on ventricular function and Holter monitoring.

Eighty-two consecutive patients with a first inferior wall acute myocardial infarction were evaluated by radionuclide angiography and 24-hour Holter monitoring during their hospital stay. The patients were divided into two groups. The first group (n = 28) had advanced atrioventricular block, while the second group (n = 54) were without atrioventricular block. The patients with advanced block had lower left ventricular (49 +/- 12% vs. 55 +/- 14%, P less than 0.05) and right ventricular ejection fraction (26 +/- 10% vs. 43 +/- 11%, P less than 0.001) than those with normal atrioventricular conduction. The atrioventricular block disappeared spontaneously in all of them. The hospital mortality of the patients with advanced block and those without advanced block was 10.7 and 5.5%, respectively (P = NS). Pre-discharge 24-hour Holter monitoring done in all survivors revealed isolated ventricular ectopics (Lown grade I, II, III) in 44% of patients who had had advanced block and 43.1% of patients without advanced block (P = NS). Complex ventricular ectopics (Lown grade IVa, IVb), however, were recorded in significantly more patients with advanced block as compared to patients without advanced block (36 vs. 7.8%, P less than 0.01). Most patients with complex ventricular ectopics in both groups had impaired left or right ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1981

Myocardial ultrastructure and the development of atrioventricular block in Kearns-Sayre syndrome.

A right ventricular endomyocardial biopsy specimen from a 30-year-old male with chromic progressive external ophthalmoplegia, retinal pigmentation and complete atrioventricular block (Kearns-Sayre syndrome) was examined in the electron microscope. There was a proliferation of mitochondria between the myofibrils and beneath the sarcolemma. Many of the mitochondria showed morphologic abnormalities not previously described in this condition. There were associated accumulations of glycogen. A similarly affected female with left anterior hemiblock developed complete atrioventricular block at age 26 years, Despite the ultrastructural changes, clinically detectable myocardial disease is not a feature of Kearns-Sayre syndrome. However, intraventricular conduction defects show an unusually rapid progression to potentially fatal complete atrioventricular block and are an indication for prophylactic cardiac pacing.

Adult↗

PubMed2000

[Therapy and prognosis of infectious complete atrioventricular block in children].

From 1983 to 1997, we have studied ten children with complete atrioventricular block likely due to myocarditis in order to assess its prognosis and to define a therapeutic strategy. Their age ranged from 6 days to 16 years (median: 4.1 years). All were admitted for sudden complete block, with symptoms in seven: syncope or fainting, seizures, collapse. Three had an asymptomatic bradycardia which was detected on routine auscultation in children with fever or already hospitalized; fever was present in 5. The disease was related to infection on biological data in 4 cases (1 listeriosis and 3 seroconversions for Epstein Barr or cytomegalic or Coxsackie B viruses), on a myocardial biposy in 1 case and on scintigraphic data in 1 case. In the remaining 4, indirect arguments were considered such as infectious context, normal recent ECG, favourable outcome. Five children were given intravenous isoprenalin with ventricular tachycardia in 3. Five were treated with steroids and 3 with specific antiviral agents. Seven patients were paced temporarily. One child died, 6 recovered totally and 3 have a permanent block with a definitive pacemaker implanted in 2. In conclusion, sudden acquired complete atrioventricular blocks are often ill-tolerated in children and have to be treated with transient pacing. Recovery occurs as a rule but some of these blocks may be definitive. Infective myocarditis is likely to be the cause of the disease even if the pathogen agent cannot always be identified.

Adolescent↗

PubMed1988

Diastolic mitral and tricuspid regurgitation by Doppler echocardiography in patients with atrioventricular block: new insight into the mechanism of atrioventricular valve closure.

The purpose of this study was to prospectively determine the incidence of diastolic mitral and tricuspid regurgitation in atrioventricular (AV) block using Doppler echocardiography. The temporal relation between mitral and tricuspid diastolic insufficiency and the diastolic murmur recorded in patients with complete heart block was also investigated. Twenty-two consecutive patients with AV block (referred to the Echo-Doppler laboratory for routine clinical studies), aged 18 to 87 years, were enrolled in the study. Eleven patients had third degree AV block and a ventricular-inhibited (VVI) pacemaker, two patients had second degree AV block, seven patients had first degree AV block, one patient had blocked premature atrial complexes and one patient had atrial flutter with 4:1 AV block. Diastolic mitral regurgitation was detected in 20 patients, and diastolic tricuspid regurgitation in 21. A mid-diastolic murmur was detected in all patients except in the three youngest. The murmur occurred before diastolic regurgitation and coincided with peak forward flow through the AV valve after atrial contraction. M-mode mitral valve echocardiograms obtained in nine patients demonstrated near closure of some portions of the mitral valve after atrial contraction. Effective closure of the valve, however, did not occur unless ventricular systole supervened. In conclusion, diastolic mitral and tricuspid regurgitation are almost universally present in patients with AV block and are associated with a diastolic murmur. The murmur coincides with forward AV valve flow. Diastolic regurgitation is silent. Effective AV valve closure is not established until ventricular systole occurs, as demonstrated by M-mode echocardiographic recording of the mitral valve.

Adult↗

PubMed1998

Supernormal conduction in a case of Mobitz type II atrioventricular block.

A 52-year-old woman exhibited Mobitz type II atrioventricular block with right bundle branch block and 1:1 atrioventricular conduction at or slower than 80 beats/min. Electrophysiologic study revealed transient HV interval block followed by recovery from the block at shorter coupling intervals without prolongation of the H1H2 and H2V2 intervals, suggesting true supernormal conduction. Isoproterenol enhanced the supernormal conduction, with shortening of blocked intervals and recovery of atrioventricular conduction, while atropine caused their less marked enhancement. Linking (ie, retrograde concealment of the impulse to the distal His bundle region through the blocked right bundle branch) is considered a possible mechanism of supernormal conduction in this case.

Atrioventricular Node↗

PubMed2003

Efficacy of corticosteroids in sarcoidosis presenting with atrioventricular block.

BACKGROUND: The usefulness of corticosteroid therapy for cardiac sarcoidosis has not yet been fully clarified. METHODS: Of 40 patients diagnosed with cardiac sarcoidosis, twenty patients complicated by atrioventricular block but normal cardiac function (left ventricular ejection fraction > or = 50%) were divided retrospectively into one group (n = 7) receiving corticosteroids and another (n = 13) not receiving these agents. Over a mean observation period of 79.4 +/- 39.9 months, long-term outcome and laboratory findings were compared between the two groups and side effects also were noted. RESULTS: There were no deaths in the corticosteroid-treated group. In the untreated group, 2 patients died (15.4%). Atrioventricular block resolved in 4 of the 7 patients in the treated group (57.1%), but did not resolve or improve in any of the untreated patients (p < 0.05). Left ventricular ejection fraction did not differ significantly between the treated and untreated groups at the time of initial evaluation (66.7 +/- 6.5% vs. 60.5 +/- 6.4%). In the follow-up period, a marked decline in the ejection fraction had occurred in the untreated group (37.6 +/- 17.3%), but not in the treated group (62.1 +/- 4.4%; p < 0.005). Ventricular tachycardia was not present at the initial assessment in any patient in either group. In the follow-up period, ventricular tachycardia occurred in only 1 of 7 treated patients (14.3%), but was present in 8 of 13 untreated patients (61.5%; p < 0.05). However, side effects of corticosteroid therapy were noted in 6 of the 7 treated patients (85.7%). CONCLUSION: Our findings suggest that corticosteroids are useful in the treatment of cardiac sarcoidosis complicated by atrioventricular block but with normal cardiac function. However, these agents must be used with caution, with the maintenance dose kept as low as possible.

Adrenal Cortex Hormones↗

PubMed1995

Complete atrioventricular block with ventricular asystole following infusion of intravenous phenytoin.

A case of complete atrioventricular block with ventricular asystole in a patient receiving intravenous phenytoin is presented. Although the potential for hypotension is generally recognized with the intravenous administration of phenytoin, conduction abnormalities are rarely reported. The differential diagnosis of atrioventricular block and the effects of phenytoin on cardiac conduction are discussed.

Aged↗

PubMed1991

[Diastolic mitral regurgitation in atrioventricular block].

Diastolic mitral block was revealed by ++Doppler echocardiography in patients with atrioventricular block degree I, II and III in atrial flutter. The leading mechanism in pathogenesis of diastolic mitral regurgitation lies in delayed contraction of the left ventricle in relation to the left atrium causing incomplete closure of mitral cusps. Other factors contributing to diastolic mitral insufficiency involve overloading of the left ventricle and rigidity of its myocardium. All the patients with atrioventricular block and diastolic mitral regurgitation showed tricuspid diastolic regurgitation. Diastolic mitral regurgitation induces volumetric overloading of the left atrium.

Aged↗